Speculatively Enable LoginScreenGuestButtonPolicyTest.HasUsers

Looks good local
Flakes are most likely related to CL:2097795

TBR=antrim@chromium.org

Fixed: 1083235
Change-Id: Ic0d3be25a1fe623681a42f45b517a596f51b8d26
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2230468Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#775087}

chrome/browser/chromeos/login/login_screen_policy_browsertest.cc

@@ -120,7 +120,7 @@ IN_PROC_BROWSER_TEST_F(LoginScreenGuestButtonPolicyTest, NoUsers) {
   EXPECT_TRUE(ash::LoginScreenTestApi::IsGuestButtonShown());
 }
 
-IN_PROC_BROWSER_TEST_F(LoginScreenGuestButtonPolicyTest, DISABLED_HasUsers) {
+IN_PROC_BROWSER_TEST_F(LoginScreenGuestButtonPolicyTest, HasUsers) {
   OobeScreenWaiter(GaiaView::kScreenId).Wait();
 
   // Default.